Hello and welcome back to Animal Wonders!

I'm Jessi, and this is Loulou! He is a half-moon conure, also known as an orange fronted parakeet.

Look at this neat thing he can do. He's turning his head totally backwards! Birds are so cool!

Many people think owls are the only birds that can turn their head all the way around, but that's not totally true, so let's delve into what makes birds so flexible and especially what makes owls so unique. [CHEERY INTRO MUSIC]. We have a lot of birds that we care for here, and I love taking them to presentations to educate about where they live, what they eat, how they survive, and their interesting adaptations. And when we get to the part about being able to turn their heads all the way around, it surprises people.

But it's actually common for most birds to tuck their heads back when they sleep, and if you watch them closely, birds spend a lot of time grooming their feathers, from their neck all the way down to their tail. Parrots like Zoe have 10 bones in their necks called cervical vertebrae, and they can't turn their head all the way around, but they can go almost 180 degrees. Want to show them? [ZOE CHIRPS] Yeah!

She has eyes on the side of her head, so like other prey animals, she's able to easily see most of the area around her, which allows her to watch out for potential predators. I always found it interesting to see parrots look down, because they don't face forward and look down. They often tilt their head to the side for better viewing with just one eye.

Now, raptors, which include eagles, hawks, falcons, owls, among others, have 14 or more vertebrae in their necks. Hara the Harris's hawk can turn her head a full 180 degrees, which allows her to groom her feathers, but the neck flexibility is also one of the important adaptations that allows her to spot prey during flight. The eye placement on the front of her head gives her binocular vision, meaning the field of vision for each eye overlaps, and this allows for more precise depth perception, which makes her an excellent hunter.

But even hawks can't turn their head completely around, and actually there isn't a single bird that can, but there is one that gets pretty close! Owls. Owls have some amazing adaptations.

And one of their most impressive is their neck. But when you look at an owl, usually the first thing that stands out is their incredible eyes. To understand why a flexible neck would be important for an owl, let's compare our human eyes to theirs.

If you hold your head completely still and then move your eyes left, right, up, and down to see as far around you as possible, you can see more than if you just stare straight forward. That's because humans have spherical eyes with 6 muscles each that can move the eye in a bunch of different directions. This allows us to look all around without having to move our heads.

But owls have eyes that are quite different. An owl's eyes are shaped like tubes, and they're held in place by bones called sclerotic rings. Their eyes don't move much, so if they want to look around, turning their whole head is the best option.

Of course, humans can turn their heads as well but not even close to how far owls can. From a front facing position, humans can turn their head about 90 degrees to the right or left. But owls?

Owls can turn their heads 270 degrees to either the left or the right! It's amazing to watch. So while owls can't actually turn their head a full 360 degrees, most people are at least familiar with the idea that owls can turn their heads really far.

Which is awesome, but knowing how they do it is even more awesome. Let's start off by comparing our necks to owl necks. Humans have 7 cervical vertebrae and owls have 14, and in some cases having more bones at one joint can increase that joint's movement and flexibility.

For example, if you hold your upper arm firmly in place and then bend your elbow, you can see it can move back and forth. This is because our elbow is a hinge joint and only has three bones, so it doesn't have much flexibility. But if you now hold your forearm in place and move your wrist, you can see there's more movement.

This is because our wrist is a synovial joint and has 4 bones, so there's more flexibility and range of motion. While there are other factors as well, there's only a difference of 1 bone between your elbow and your wrist, so imagine the difference seven bones can have on an already quite flexible part of your body, like your neck. And an owl's neck is way more flexible than ours due to the number of cervical vertebrae and also the shape of those bones.

So if we imagined that we have 14 specially shaped cervical vertebrae in our necks like an owl, we should be able to turn our heads 270 degrees and look behind us, right? Nope, we still can't! Because there's something else that makes owls extra special.

This is something you've probably never thought of being a problem with simply turning your head, and it's kinda weird but super serious. If we turned our heads as far as owls, we would actually cause ourselves to have a stroke. Some strokes occur when blood flow is cut off to part of your brain.

And to protect our blood vessels when we turn our head, the bones in our neck have small holes for them that are just big enough to allow them to fit. They keep the vessels tucked in safely against our neck bones. But this means if we turn our necks really far like an owl can, it would cause a strain on the trapped vessels and they would likely get stretched, pinched, or torn in the process.

And without the proper flow of blood, your brain won't get the oxygen it needs and within minutes, your brain cells would start to die. So, how do owls get around this problem? Well, there's actually quite a few adaptations that allow for their amazing flexibility in their necks.

First, they have very special bones and blood vessels. If we look closely at the cervical vertebrae in an owl's neck, we can see that the holes for their blood vessels are 10 times larger than their vertebral artery. So when they turn their neck, the arteries aren't trapped which causes less strain.

Next, the first two vertebrae in an owl's neck don't have holes along the side like the others, so the arteries have much more slack when the neck is turned. Also, both arteries are positioned close to the axis of rotation. So the chances of pinching or overly straining them is greatly decreased.

And, the vertebral artery enlarges as it nears the top of the neck and the base of the skull. Which is interesting, because the general rule for arteries in humans is that they get smaller the farther they are from the heart. But for owls, this enlargement allows for a small amount of pooling of fresh oxygenated blood right after the neck.

So, if the owl is twisting its head, and blood flow is restricted, it's hypothesized that there's still a small amount of fresh blood that the brain can use to avoid a stroke. Which is just so much more in depth than you've probably ever thought about an owl doing its iconic head tilt and turn. So owls have really impressive adaptations that allow them to turn their heads upside down and 270 degrees around, and now you know how they can do it.

But their neck is only one of the awesome adaptations they have. What makes owls amazing in my eyes is that they are perfectly adapted to their environment. Like they have silent flight to sneak up on their prey, they have excellent hearing but pretty unusual ear placement, and of course their fascinating eyes and amazing night vision.

And keep in mind that many of the things we know about bird anatomy and owls' superb neck turning abilities are still being studied, so we don't know everything yet, and I'm excited that I get to keep learning as more discoveries are made! Thanks for watching, and I hope I've inspired you to keep wondering about what makes owls so special. And if you'd like to help support our efforts to share the wonders of animals with everyone, you can join our community on Patreon by going to patreon.com/animalwonders.

And if you'd like to keep learning and going on adventures with us every week, be sure to subscribe and we'll see you very soon. Bye! [BOLD OUTRO MUSIC].